Page 21 - February 2022

person to recommend a cavalier approach in the cockpit. However, IF you know the capabilities and limitations of your aircraft well, you can gently bend a rule here or there to find a safe way out of a less-than-optimal situation. That’s a big “IF” and I trust you readers are getting my intention here.
Skipping the Test
When my customer brought his B200 over to my shop, that solenoid was still stuck open. I cured it with a whack of a mallet and suggested he skip the overspeed governor test from now on. All it does is test the solenoid. It doesn’t, in my opinion, directly test the function of the overspeed governor itself. Some may disagree with me on this, but there are many seasoned King Air pilots with thousands of King Air hours who agree wholeheartedly with omitting the OSG test before takeoff.
The same thing happened to the pilot of an E90 down in Alabama. He was picking up the aircraft following a Phase Inspection. The shop had just finished checking all the systems (pressurization, autofeather, auto-ignition, overspeed governors, etc.) so the pilot wasn’t expecting anything to be amiss. But as he was about to take off, he noticed one prop RPM lagging below the other.
He had my number in his cellphone and gave me a call right then and there. He described the problem, and I knew right away that the OSG solenoid was stuck open. I told him to taxi back to the shop, tell them he had spoken to me about the problem, and have them smack the OSG solenoid with a mallet. That did the trick!
I gave the E90 pilot the same advice to quit testing the overspeed governor because you’re just asking for a stuck solenoid.
The Power Lever Double-check
Back in the ‘70s and ‘80s, we had a chronic problem with those solenoids sticking open. We would execute the final ground runs on a King Air and everything would be fine ... but when the owner went to leave, one prop wouldn’t come up to takeoff RPM. It happened frequently and it was maddening.
In response, I formed the habit of releasing the OSG test switch and running the power levers back up through the test zone. This way, if the solenoid stuck open after the test, I could catch it on my ground run and fix it before the owner picked up his aircraft. To this day, if I touch that OSG test switch, I do a double-check with the power levers afterward.
FEBRUARY 2022
KING AIR MAGAZINE • 19